On 08.07.22 06:17, Stefan Hajnoczi wrote:
Emulated devices and other BlockBackend users wishing to take advantage
of blk_register_buf() all have the same repetitive job: register
RAMBlocks with the BlockBackend using RAMBlockNotifier.
Add a BlockRAMRegistrar API to do this. A later commit will use this
from hw/block/virtio-blk.c.
Signed-off-by: Stefan Hajnoczi <[email protected]>
---
MAINTAINERS | 1 +
include/sysemu/block-ram-registrar.h | 30 +++++++++++++++++++++
block/block-ram-registrar.c | 39 ++++++++++++++++++++++++++++
block/meson.build | 1 +
4 files changed, 71 insertions(+)
create mode 100644 include/sysemu/block-ram-registrar.h
create mode 100644 block/block-ram-registrar.c
What memory is handled in ram_list? Is it everything? If so, won’t
devices have trouble registering all those buffer, especially if they
happen to be fragmented in physical memory? (nvme_register_buf() seems
to say it can run out of slots quite easily.)
diff --git a/MAINTAINERS b/MAINTAINERS
index 50f340d9ee..d16189449f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2490,6 +2490,7 @@ F: block*
F: block/
F: hw/block/
F: include/block/
+F: include/sysemu/block-*.h
F: qemu-img*
F: docs/tools/qemu-img.rst
F: qemu-io*
Sneaky. ;)
diff --git a/include/sysemu/block-ram-registrar.h
b/include/sysemu/block-ram-registrar.h
new file mode 100644
index 0000000000..09d63f64b2
--- /dev/null
+++ b/include/sysemu/block-ram-registrar.h
@@ -0,0 +1,30 @@
+/*
+ * BlockBackend RAM Registrar
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef BLOCK_RAM_REGISTRAR_H
+#define BLOCK_RAM_REGISTRAR_H
+
+#include "exec/ramlist.h"
+
+/**
+ * struct BlockRAMRegistrar:
+ *
+ * Keeps RAMBlock memory registered with a BlockBackend using
+ * blk_register_buf() including hotplugged memory.
+ *
+ * Emulated devices or other BlockBackend users initialize a BlockRAMRegistrar
+ * with blk_ram_registrar_init() before submitting I/O requests with the
+ * BLK_REQ_REGISTERED_BUF flag set.
s/BLK/BDRV/, right?
+ */
+typedef struct {
+ BlockBackend *blk;
+ RAMBlockNotifier notifier;
+} BlockRAMRegistrar;
+
+void blk_ram_registrar_init(BlockRAMRegistrar *r, BlockBackend *blk);
+void blk_ram_registrar_destroy(BlockRAMRegistrar *r);
+
+#endif /* BLOCK_RAM_REGISTRAR_H */
